The present invention relates to stencils and stenciling methods.
A stencil is a, typically impervious, film or sheet of material perforated with one or more designs (e.g., lettering or an artistic shape). As used, a stencil is typically contacted with a surface of a substrate, and a colorant (e.g., ink, paint, glaze, or metallic powder) is applied to the surface through perforation(s) in the stencil. After application of the colorant, the stencil is removed from the surface leaving behind a corresponding design on the surface. By this method, decorative designs are frequently applied to walls, ceilings, papers, ceramics, metals, glass, and wood furniture to enhance the attractiveness of an area or object and/or as a form of recreation.
While applying the colorant to the surface of the substrate, any movement of the stencil typically degrades the quality of the resulting design. Common methods for securing stencils to the substrate surface include application of hand pressure, taping the stencil to the surface of the substrate, and/or using an adhesive between the stencil and the surface of the substrate.
Stencils that are secured by taping around the perimeter are often difficult and awkward to secure because sufficient area must be left around the stencil to tape to the substrate. They are also prone to unacceptable shifting of the template, particularly in design areas that are masked by narrow elements of the stencil sheet or require interior projections, unless the template is made very rigid. Rigid stencils are generally difficult to use with rounded or uneven substrate surfaces.
The abovementioned methods using adhesives can be awkward to carry out, may cause damage to substrates upon their removal (e.g., paint removal), or leave a residue that must be separately removed. Also, adhesives may not adhere well to substrates that are covered with a layer of extraneous material (e.g., dust).
Plasticized vinyl films (commonly referred to as xe2x80x9ccling vinylxe2x80x9d films) have been used as stencils. These stencils typically adhere well to smooth substrates, but generally do not adhere well to rough or dusty surfaces (e.g., painted drywall) or porous or uneven surfaces (e.g., wood, brick).
Electret films, that is, films having a permanent or semi-permanent electrostatic charge (i.e., electret charge), have been prepared using a variety of thermoplastic polymers. Electret films generally exhibit electrostatic attraction (i.e., static cling) to the surfaces of substrates allowing the films to be removably adhered to such surfaces.
Polymeric electret films, in sheet or roll form, with lines of minute perforations to facilitate tearing are known and are commercially available. However, such lines of perforations are separated from each other by a relatively large distance (typically the length of a sheet), and are not suitable for use as a stencil.
It would be desirable to have stencils that overcome at least some of the deficiencies listed above.
In one aspect, the present invention provides a stencil comprising an electret film having a first major surface, a second major surface opposed to the first major surface, and at least one perforation extending through the film and connecting the first and second major surfaces, wherein the perforation has a perimeter that defines an area, and wherein the area is greater than or equal to about one square centimeter.
In another aspect, the present invention provides a method for marking a substrate comprising:
providing an electret film having first and second opposed major surfaces, the electret film having at least one perforation therethrough;
providing a substrate having a surface;
electrostatically and removably adhering the first major surface of the electret film to the surface of the substrate;
applying a medium to the surface of the substrate through said at least one perforation; and
removing the electret film from the surface of the substrate.
In another aspect, the present invention provides an imaged article prepared according to the abovementioned method.
Stencils according to the present invention are typically easily positioned, repositionable, easily removable without leaving any adhesive residue, and securely held to the substrate during stenciling.
As used herein:
xe2x80x9cfilmxe2x80x9d includes sheets and strips; and
xe2x80x9c(meth)acrylxe2x80x9d includes acryl and methacryl.